Can this scenario be modelled within Excel?

[gravanoc]

The purpose is to ensure that an expected number of new clients will be served by a sales representative on schedule. Normally, you hire sales reps and then get clients, but for the purposes of forecasting I need to do it the other way around. Each sales rep, newly hired, has a training period of 2.0 quarters, and then they can establish a new client over a period of 3.0 quarters. Since they don't need to go through training again they can continue to establish clients at that same rate (3.0 quarters). I have created an example of how this would work above, so the red area is training, any blue color (I varied it to help distinguish from other rows) is the interim of establishing a client, and green is the completed sale. The purpose though is to find a formula which can dynamically do this, and adjust based on different numbers of clients (entered in Row 10). Clients are cumulative, which is shown in Row 11.

I have attached the sheet where it makes it a bit easier to understand what I'm saying. I would prefer this to use a formula if possible, but VBA is acceptable. If it doesn't sound like it's possible with Excel, please recommend a program that might be better suited for it.

https://drive.google.com/file/d/1HEZ95OW9QFu2ICC0WmTsAYTcZbfXsyjh/view?usp=sharing